Sporotrichosis

Definition

Photomicrograph showing Sporothrix schenckii.

What is sporotrichosis?

Sporotrichosis (also known as “rose gardener’s disease”) is a rare infection caused by a fungus called Sporothrix. This fungus lives throughout the world in soil and on plant matter such as sphagnum moss, rose bushes, and hay.1,2 People get sporotrichosis by coming in contact with the fungal spores in the environment. Cutaneous (skin) infection is the most common form of the infection. It occurs when the fungus enters the skin through a small cut or scrape, usually after handling contaminated plant matter. Some cases of sporotrichosis have been associated with scratches or bites from animals, particularly cats.

Types of sporotrichosis

Cutaneous (skin) sporotrichosis is the most common form of the infection. It usually occurs on a person’s hand or the arm after they have been handling contaminated plant matter.

Pulmonary (lung) sporotrichosis is very rare but can happen after someone breathes in fungal spores from the environment.

Disseminated sporotrichosis occurs when the infection spreads to another part of the body, such as the bones, joints, or the central nervous system. This form of sporotrichosis usually affects people who have weakened immune systems, such as people with HIV infection (see Risk & Prevention).

Symptoms

The symptoms of sporotrichosis depend on where the fungus is growing. Contact your healthcare provider if you have symptoms that you think are related to sporotrichosis.

Sporotrichosis usually affects the skin or tissues underneath the skin. The first symptom of cutaneous (skin) sporotrichosis is usually a small, painless bump that can develop any time from 1 to 12 weeks after exposure to the fungus. The bump can be red, pink, or purple, and it usually appears on the finger, hand, or arm where the fungus has entered through a break in the skin. The bump will eventually grow larger and may look like an open sore or ulcer that is very slow to heal. Additional bumps or sores may appear later near the original one.

Pulmonary (lung) sporotrichosis is less common than the cutaneous (skin) form of the infection. Symptoms include cough, shorthess of breath, chest pain, and fever.

Symptoms of disseminated sporotrichosis depend on the body part affected. For example, infection of the joints can cause joint pain that may be confused with rheumatoid arthritis. Infections of the central nervous system can involve difficulty thinking, headache, and seizures.

Risk & Prevention

Who gets sporotrichosis?

Overall, sporotrichosis is rare, but people who handle plant matter such as sphagnum moss, rose bushes, or hay are more likely to get the infection. For example, sporotrichosis outbreaks have occurred among forestry workers, people who worked in tree nurseries and garden centers, and people who handled hay bales.

The severe forms of sporotrichosis (those that affect the lungs, bones or joints, or central nervous system) usually affect people with weakened immune systems or underlying diseases including diabetes, chronic obstructive pulmonary disease (COPD), alcoholism, or HIV infection.1,3,4

How can I lower the chance of developing sporotrichosis?

You can lower the chance of getting sporotrichosis by wearing protective clothing such as gloves and long sleeves when handling plant matter that can cause minor cuts or scrapes.

Sources

Sporotrichosis is often associated with sphagnum moss, rose bushes, hay, or animal scratches or bites.

The fungus that causes sporotrichosis lives in the environment.

Sporothrix, the fungus that causes sporotrichosis, lives in the environment in soil and on plant matter such as sphagnum moss, rose bushes, hay, or wood. The microscopic fungus can enter the skin through small cuts or scrapes. In rare cases, breathing in the fungus can cause pulmonary (lung) infection. Sporotrichosis is not contagious and can’t spread from person to person. Some cases are caused by scratches or bites from animals, particularly cats (however, this is not the same as cat-scratch disease).

Diagnosis & Testing

How is sporotrichosis diagnosed?

Sporotrichosis is typically diagnosed when your healthcare provider takes a small tissue sample (biopsy) of the infected area of the body. The sample is sent to laboratory for tests (usually a fungal culture) to find out what is causing the infection. Blood tests can help diagnose severe sporotrichosis, but they often can’t diagnose a cutaneous (skin) infection.

Treatment

How is sporotrichosis treated?

Most cases of sporotrichosis only involve the skin or the tissues underneath the skin. These infections are not life-threatening but must be treated with prescription antifungal medication for several months. The most common treatment for this type of sporotrichosis is itraconazole, taken by mouth for 3 to 6 months. Supersaturated potassium iodide (SSKI) is another treatment option for cutaneous (skin) sporotrichosis. However, SSKI and azole drugs like itraconazole should not be used during pregnancy.

Patients with severe forms of sporotrichosis are usually treated with amphotericin B, which is given through a vein. Itraconazole is often used after the initial treatment with amphotericin B, for a total of at least 1 year of antifungal treatment. People with sporotrichosis in the lungs may also need surgery to cut away the infected tissue.

Statistics

How common is sporotrichosis?

Sporotrichosis is rare, but the number of cases is difficult to determine because there is no national surveillance for it in the United States. Population-based incidence estimates for sporotrichosis were obtained from laboratory surveillance in the San Francisco Bay Area during 1992–1993 and suggested a yearly rate of less than one case per 1 million population.5 Sporotrichosis may be more common in other parts of the world such as Latin America.2 For example, in the state of Rio de Janeiro, Brazil, more than 2,200 cases were reported during 1998–2009.6 Another study suggested a rate of 48 to 60 sporotrichosis cases per 100,000 population in the south central highlands of Peru.7

Sporotrichosis outbreaks

In the United States, sporotrichosis outbreaks have occurred among people who handled sphagnum moss or hay, such as forestry workers,8,9 tree nursery and garden center workers,10-12 and people who worked with or played on hay bales.13-16 Sporotrichosis outbreaks also have been reported in several other countries, including Australia, Brazil, China, Guatemala, and South Africa.2 Healthcare providers who are concerned about an unusual number of new cases should contact their state or local public health agency.